The US branch of Best Buy has launched another iPhone trade-in promotion, running today through August 18th. People who bring an iPhone 4S into a Best Buy store can get a gift card towards an iPhone 5 worth at least $200, so long as the phone is working and undamaged. A similar deal exists for people trading in an iPhone 4, although the base gift card value starts at only $100.

In both cases iPhone 5 buyers must pick up a phone with a fresh two-year contract for AT&T, Sprint, or Verizon; T-Mobile and unlocked models are ineligible. Nevertheless, Best Buy is likely trying to clear out old stock ahead of the announcement of new iPhones next month. Apple is expected to ship two devices, the iPhone 5S and 5C, by the end of September.